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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28057 results found.

  1. GRB 210618A: DDOTI upper limit for the optical afterglow
  2. GRB 210618A: Swift detection of a burst
  3. GRB 210610B: Swift/UVOT Detection
  4. GRB 210610A: Swift/UVOT Detection
  5. GRB 210323B: Fermi GBM observation
  6. GRB 210610B: REM optical/NIR observations of the afterglow
  7. Follow-up on HAWC Transient Monitoring Alert J0020+3108
  8. Swift ToO Observations of HAWC transient J0020+3108
  9. GRB 210605B: Swift-XRT afterglow detection
  10. GRB 210610A: Fermi GBM observations
  11. GRB 210610B: Further SAO RAS optical observations
  12. GRB 210610A: SAO RAS optical observations
  13. GRB 210610B: optical photometry of afterglow at INASAN/Simeiz
  14. GRB 210421B: Fermi GBM detection
  15. GRB 210607C: AstroSat CZTI detection
  16. Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
  17. GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
  18. GRB 210610B: MITSuME Akeno optical observation
  19. GRB 201228B: Fermi GBM observation
  20. GRB 210610B: Liverpool Telescope optical photometry
  21. GRB 210610A: CrAO/ZTSH optical observations
  22. GRB 210610B: CrAO/ZTSH optical observations (correction to the GCN circ. 30212)
  23. GRB 210610A: CrAO/ZTSH optical observations
  24. GRB 210606A: Fermi GBM detection
  25. GRB 210605B: Fermi GBM detection
  26. GRB 210610B: Swift-XRT refined Analysis
  27. GRB 210610B: Swift-BAT refined analysis
  28. GRB 210610B: Zwicky Transient Facility afterglow detection
  29. GRB 210610B: optical afterglow observations
  30. GRB 210607C: Insight-HXMT/HE detection
  31. GRB 210610B: Fermi GBM detection
  32. GRB 210610B: University of Siena Observatory optical photometry of the afterglow
  33. GRB 210610B: GOTO confirmation of afterglow detection
  34. GRB 210610A: Swift-XRT refined Analysis
  35. GRB 210610A: RATIR Optical and NIR Detection
  36. GRB 210610B: RATIR Optical and NIR Observations
  37. GRB 210610B: Enhanced Swift-XRT position
  38. GRB 210610B: SAO RAS optical observations
  39. GRB 210610A: Swift-BAT refined analysis
  40. GRB 210610B: correction to GCN 30181
  41. HAWC Transient Monitoring Alert: Significant Spot after 3 transits
  42. GRB 210610B: iTelescope optical afterglow observations
  43. GRB210610B: MeerLICHT multi-colour photometry
  44. GRB 210610B: CrAO/ZTSh optical afterglow photometry
  45. GRB 210610B: GIT optical detection
  46. Swift GRB210610.83: Global MASTER-Net OT detection
  47. GRB 210606A: Swift-XRT afterglow detection
  48. GRB 210610B: BALROG localization (Fermi Trigger 645047470 / GRB 210610827)
  49. GRB 210610B: Swift detection of a burst with bright optical afterglow
  50. GRB 210610A: MITSuME Ishigaki optical observation
  51. GRB210610A: MeerLICHT multi-colour photometry
  52. GRB 210610A: Enhanced Swift-XRT position
  53. GRB 210610A: GIT optical detection
  54. GRB 210610A: Xinglong-2.16m optical afterglow observations
  55. GRB 210610A: MITSuME Akeno optical observation
  56. GRB 210610A: Swift detection of a burst with an optical counterpart
  57. GRB 210607B: Insight-HXMT/HE detection
  58. Fermi-LAT Gamma-ray Observations of IceCube-210608A
  59. IPN triangulation of GRB 210606B
  60. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  61. MAXI GRB210607.82: Global MASTER-Net observations report
  62. Fermi trigger No 644793834: Global MASTER-Net observations report
  63. GRB 210606B: Fermi GBM detection
  64. GRB 210605B: Swift-XRT observations
  65. IPN triangulation of GRB 210605A (short)
  66. GRB 210606B: BALROG localization (Fermi Trigger 644712030 / GRB 210606945)
  67. GRB 210606B: GECAM detection
  68. Fermi GRB 210606A: DDOTI Upper Limits on the Afterglow
  69. GRB 210606A: Swift/BAT-GUANO detection and arcminute localization
  70. GRB 210605B: Swift/BAT-GUANO detection and arcminute localization
  71. Initial results of a NICER X-ray monitoring of the magnetar, Swift J1555.2-5402
  72. Fermi GBM Sub-Threshold Detection of new Swift SGR J1555.2-5402
  73. SGR J1555.2-5402: Swift-BAT refined analysis
  74. NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
  75. Swift Detection of probable new Swift SGR J1555.2-5402
  76. MAXI GRB210602.50: Global MASTER-Net observations report
  77. Swift GRB210603.41: Global MASTER-Net observations report
  78. GRB 210602B: GECAM detection
  79. GRB 210529A: GECAM detection
  80. GRB 210602A: MAXI/GSC detection
  81. GRB 210601A: Fermi GBM Final Real-time Localization
  82. IPN triangulation of GRB 210531A
  83. GRB210529B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 644025222)
  84. GRB 210531A: AstroSat CZTI detection
  85. Fermi trigger No 644155206: Global MASTER-Net observations report
  86. GRB 210531A: BALROG localization (Fermi Trigger 644155206 / GRB 210531500)
  87. GRB 210529B: DDOTI Upper Limits on the Afterglow
  88. GRB 210528A: Fermi GBM detection
  89. GRB 210528A: AstroSat CZTI detection
  90. GRB 210528B: DDOTI Upper Limits on the Afterglow
  91. GRB 210528B: MITSuME Akeno optical upper limits
  92. MAXI GRB210528.95: Global MASTER-Net observations report
  93. GRB 210528B: MAXI/GSC detection
  94. GRB 210527A: Swift-BAT refined analysis
  95. GRB 210528A: BALROG localization (Fermi Trigger 643903431 / GRB 210528586)
  96. GRB 210527A: Swift/UVOT Observations
  97. GRB 210527A: GIT optical upper limit
  98. GRB 210527A: MITSuME Akeno optical upper limits
  99. GRB 210527A: Swift-XRT refined Analysis
  100. GRB 210527A: RATIR Optical and NIR Observations

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